Inorganic thin films self-assembled from lamellar TiO/sub 2/ and layered double hydroxide and their electrochemical behaviour

Inorganic thin films composed of nanoplatelets of Ni and Co containing layered double hydroxides (LDH) and exfoliated TiO₂ have been fabricated onto various substrates via the electrostatic self-assembly technique. Dense coverage of the substrate surface by the nanoplatelets was visualized confirmed by scanning electron microscopy. UV-vis absorption spectroscopy provided evidence for the subsequent growth of multilayer, exhibiting progressive enhancement of the optical absorption due to exfoliated TiO₂. Evolution of a Bragg peak also supported the growth of nanostructured film of TiO₂/Ni(Co)Al-LDH. Cyclic voltammogram measurements revealed both reduction and oxidation peaks from the film, which are attributable to the electrochemical conversion between the different valence states of transition metals in the films.